The overall objective of this project is to apply our approach for estimating "trophic condition," and net ecosystem metabolism (NSM) to shallow areas of the Chesapeake Bay. Specific goals include: measure planktonic and benthic P and R along cross-bay depth gradients; relate NSM with O2 (% sat) and chl a within shallow and between channel stations and shoal areas; develop improved estimates of ecosystem NSM for the whole Bay; estimate the contribution of NSM in mesohaline shoals to inputs of particulate organics to subpycnocline waters in adjacent deeper areas; use this improved method for estimating NSM to deduce interannual patterns of NSM in the Bay and to relate these to changes in nutrient loading and hydrological conditions.